Depot Market Square Permeable Pavement - Stormwater Discovery Tours

Where is this located? It is in the center of the Depot Market Square parking lot.

What’s special about this place? In permeable paver systems such as that used at the Depot Market Square, the pavement itself is not permeable. However, the gaps between the pavers do allow runoff to soak in. Water does not flow through the pavers as they are just made of regular concrete. Below the pavers, a treatment layer of sand provides some water quality treatment. Permeable pavement does provide some flow control slowing the runoff down.

About Permeable Pavement

Permeable pavements include pervious concrete, porous asphalt, and spaced pavers, which are installed over special layers of sand, gravel, and soil. Pervious concrete and porous asphalt have small spaces that allow stormwater to soak through them, while interlocking pavers allow water to soak between the pavers. In addition to reducing runoff, permeable pavements help filter out pollutants. Because they are capturing and retaining pollutants, it is necessary to regularly clean the pavement or gaps between pavers to maintain their permeability.

Water quality benefit: Permeable pavement surfaces are effective in managing runoff from paved surfaces because they capture and absorb stormwater runoff at the source. When water soaks through permeable pavements, it prevents pooling of water on the surface. Permeable pavements are also effective at trapping pollutants as the runoff filters through the underlying layers of sand and gravel.

Use this button below to open map in Google Maps or skip map

drainage area

Drain 1/10th of an acre.

Where does this stormwater runoff come from? The stormwater at this site comes from rain that falls on the permeable pavers in the center of the Depot Market Square.

Where does this stormwater runoff flow next? Most of the rain that falls on this part of the parking area soaks into the ground below the pavers. If there is too much runoff it is collected by catch basins along Railroad Avenue where it flows through pipes that carry the water over the hill below Laurel Street to an outfall in the Whatcom Waterway.

image gallery

select any photo to see a slideshow